ROLE OF CMYBP-C IN THE REGULATION OF MYOCARDIUM

CMYBP-C 在心肌调节中的作用

• 批准号: 7954897
• 负责人: Richard L Moss
• 金额: $ 3.26万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7954897
• 关键词: Ablation; Actins; Affect; Binding; Biophysics; Cardiac; Cardiac Myosins; Charge; Computer Retrieval of Information on Scientific Projects Database; Cyclic AMP-Dependent Protein Kinases; Funding; Genetic; Grant; Heart failure; Institution; Mediating; Mutant Strains Mice; Mutation; Myocardium; Myosin ATPase; Phosphorylation; Positioning Attribute; Proteins; Radial; Regulation; Research; Research Personnel; Resources; Role; Serine; Site; Source; Surface; Testing; Thick Filament; Thin Filament; Threonine; Troponin I; United States National Institutes of Health; X ray diffraction analysis; X-Ray Diffraction; citrate carrier; inorganic phosphate; mutant; myosin-binding protein C; protein structure

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cardiac myosin binding protein-C (cMyBP-C) phosphorylation changes in heart failure and may be a significant modulator of cardiac function. We have recently shown that both genetic ablation and protein kinase A-mediated (PKA) phosphorylation of cMyBP-C appear to result in radial or azimuthal displacement of myosin cross-bridges, such that cross-bridges are located further from the surface of the thick filament of myosin and closer to the thin filament of actin. Reversible PKA phosphorylation of myofibrillar proteins, such as cMyBP-C, involves the addition of a negatively charged phosphate (PO4) molecule on a serine or threonine residue, which induces a conformational change in the structure of the protein. While we have found PKA phosphorylation of cMyBP-C to modulate the disposition and availability of cross-bridges to actin, it remains unresolved whether or not this mechanism of cMyBP-C function is attributed to the negative charge associated with phosphorylation. To test this, we assessed the intensities of equatorial reflections (I11/I10) using low-angle X-ray diffraction to determine the position of cross-bridges in myocardium from four lines of mutant mice. The mutations include four pertinent states of myofibrillar phosphorylation: non-phosphorylatable cMyBP-C mutant protein, constitutively-phosphorylated cMyBP-C mutant protein, normal cMyBP-C protein, and normal cMyBP-C expressed with non-phosphorylatable cardiac troponin I (cTnI) since cTnI phosphorylation also affects contraction. We hypothesize that the negative charge associated with phosphorylation of PKA sites in cMyBP-C will be sufficient to relieve a physical constraint on cross-bridges, possibly by disrupting cMyBP-C binding to the S2-region of myosin.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 心力衰竭的心脏肌球蛋白结合蛋白-C（CMYBP-C）磷酸化变化，可能是心脏功能的重要调节剂。我们最近表明，CMYBP-C的遗传消融和蛋白激酶A介导的（PKA）磷酸化似乎会导致肌球蛋白跨支架的径向或方位角位移，因此跨支架距离肌球蛋白的厚细胞和靠近薄丝的薄丝的表面更远。肌原纤维蛋白（例如CMYBP-C）的可逆PKA磷酸化涉及在丝氨酸或苏氨酸残基上添加带负电荷的磷酸盐（PO4）分子，从而诱导蛋白质结构的构象变化。虽然我们发现CMYBP-C的PKA磷酸化调节了跨桥对肌动蛋白的处置和可用性，但是否尚未解决CMYBP-C功能的这种机制是否归因于与磷酸化相关的负电荷。为了测试这一点，我们使用低角度X射线衍射评估了赤道反射（I11/I10）的强度，以确定从四个突变小鼠的心肌中跨桥的位置。这些突变包括四个相关的肌原磷酸化状态：不可磷酸磷酸化的CMYBP-C突变蛋白，组成型磷酸化的CMYBP-C突变蛋白，正常的CMYBP-C蛋白，正常CMYBP-C，正常CMYBP-C与非磷酸化的心脏troponin i（CTRACTION）cTNI（CTNI）均为CTNI（CTNI）。我们假设与CMYBP-C中PKA位点磷酸化相关的负电荷足以通过破坏CMYBP-C与肌球蛋白S2区域的结合来缓解对跨桥的物理约束。